The spectral-kinetic characteristics of luminescence of 17 polycyclic aromatic hydrocarbons (PAH) sorbed from a “water-organic solvent” medium on cellulose diacetate (CDA) matrices were studied. A significant increase in the fluorescence signal on the CDA matrix was observed for 13 PAHs in comparison with aqueous solutions. The highest detection sensitivity was found for pyrene, benzo(a)pyrene, and benzo(k)fluoranthene. The fluorescence spectra of two PAH indicator pairs (anthracene–phenanthrene and pyrene–fluoranthene) used to control toxicant emission sources were studied with the simultaneous presence of isomers in the analyte, depending on the excitation wavelength. For both isomer pairs, it has been found that the spectra of their solid-state luminescence overlap insignificantly, the characteristic peaks do not coincide and do not overlap, the sensitivities of detection are close to each other, which makes it possible to consider this technique as promising to control PAH contamination sources.
The isolated and combined effect of heliogeophysical factors and low intensive electromagnetic radiation of millimeter diapason at the metachromasia reaction of the yeast Saccharomyces cerevisiae was studied. It was established that longterm influence of EMR 65 GHz induced changes in the response of cells towards heliogeomagnetic disturbance. On our opinion millimeter waves may reduce the effect of heliogeophysical factors on living organisms because of destabilization of the intracellular water structure.
We analyzed literature data about structures of ligands of CCKB receptor. The structure of the binding site (fragments of
the third extracellular loop and the seventh transmembrane helix of CCKB receptor) was determined recently by
experiments. We were finding presumable biologically active conformations (BAC) of the ligands by two methods. One
of them is based on the fact that the most stable conformations of the biologically active peptide on the phase interface
"water-lipophilic medium" are often similar to the BAC. Another method is based on the formation of the stable ligand-receptor
complex during the modeling procedure. We used Monte-Carlo method with the fixed geometry of the receptor
and the optimized geometry of tetrapeptide cholecystokinin (CCK-4). It has been shown, that the first method should be
used to find BAC of antagonists of CCKB receptor. The strategy of the formation of the stable ligand-receptor complex
during the modeling procedure can be used for the designing of peptide agonists of CCKB receptor.
In this paper we propose a theoretical method of estimation of biological activity of tetrapeptide cholecystokinin (CCK-
4) analogues according to their structure. The method is based on the prospective mechanism of CCK-4 interaction with
CCK-2 receptor. Electron and structural properties of CCK-4 are taken into account. The relationship structure-activity
for CCK-4 analogues with the known pharmacological profile have been studied using the model of the ligand-receptor
interaction.
It is well known that weak electromagnetic fields of extremely high frequencies cause significant modification of the
functional status of biological objects of different levels of organization. The aim of the work was to study the
combinatory effect of metronidazole - the drug form of 1-(2'hydroxiethil)-2-methil-5-nitroimidazole - and
electromagnetic radiation of extremely high frequencies (52...75 GHz) on the hemolytic stability of erythrocytes and
hemotaxis activity of Infusoria Paramecium caudatum.
Fluorescence and spectrophotometric methods have been used for investigation of nicotine action on the state and mobility of the surface water. The surfaces of membranes and proteins were simulated with the help of liposomes and ultradispersive diamonds consequently. Nicotine was shown to reduce the stability of liposomes and to change the aggregative ability of ultradispersive diamonds. The wave-like curves for the nicotine concentration dependences of the pointed features were observed. Such shape of responses was suggested to be due to the changing in structure and dynamics of water hydrogen bonds net near the surface of the model systems induced by nicotine molecules. The surface water phase was supposed to be one of signal elements ofthe ligand receptor recognition process.
KEYWORDS: Molecules, Hydrogen, Computer simulations, Chemical compounds, Chemical species, Software, Correlation function, Molecular interactions, Analog electronics, Data modeling
Computer simulation of aqueous solutions of some biological active and inactive compounds has been carried out. Molecular dynamics method and TIP3P potential were used. The parameters of hydrogen bonds net were calculated by using the developed computer program. The simulation showed that relatively large clusters of water molecules appeared and the average number of hydrogen bonds decreased in the aqueous solutions of biological active compounds. It points to the fact that these compounds may induce the phase k-transition in the surrounding water. Molecular mechanisms ofthese effects are discussed.
Spectrophotometric and fluorescence methods have been used for creation and investigation of various systems of target delivery of chemical compounds to roots of plants. The possibility of using liposomes, incrusted by polysaccharides of the external surface of nitrogen-fixing rizospheric bacteria Azospirillum brasilense SP 245, and nanoparticles incrusted by polysaccharides of wheat roots, as the named systems has been shown. The important role of polysaccharide-polysaccharide interaction in the adsorption processes of bacteria on wheat roots has been demonstrated.
Photometric and fluorescence methods have been used for investigation of the drug 1-(2'hydroxiethil)-2-methil-5nitroimidazole (metronidazolum) action on the stability of erythrocytes and liposomes and on the protein folding. Metronidazolum was shown to protectively act on the cell membranes. Besides the compound was able to decrease the folding rate of the protein catalase. The molecular mechanism of the compound effect on the cell membranes and proteins was supposed to be modification of the hydrogen bonds net of the surface water. The last was proved by the results of molecular dynamics computation of parameters of hydrogen bonds net and clusters of water molecules in metronidazolum solution and in the solutions of inactive compounds.
We have studied morphine action on mobility and structure of water by means of fluorescent investigations and light scattering analysis. Wave-like concentration dependences have been plotted in the both cases. Theoretical description of the discovered effect has been made based on the formalism of N.N.Bogolubov.
We have studied the conformational properties and molecular dynamics of polysaccharides by using molecular modeling methods. Theoretical and experimental results of polysaccharide-polysaccharide interactions are described.
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